[PATCH] [ARM64]Fix a bug when lowing shuffle vector to EXT instruction

[Hao Liu]

Hi Tim,

Yes. As "(1). *FirstRealElt - (FirstRealElt - M.begin())" may be overflow, this patch implements in "(2). ExpectedElt - NumElts".

I think you mean this patch is OK to be committed. Committed in http://llvm.org/viewvc/llvm-project?view=revision&revision=207485.

Thanks,
-Hao

http://reviews.llvm.org/D3500